کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6440136 1638361 2013 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Temporal variation in volcanic ash texture during a vulcanian eruption at the Sakurajima volcano, Japan
ترجمه فارسی عنوان
تغییرات زمانی در بافت خاکستر آتشفشانی در طی فوران ولکانانی در آتشفشان ساکارجیما، ژاپن
کلمات کلیدی
فوران ولکانایی، بافت خاکستر آتشفشانی، مجموعه زمان واقعی تنوع زمانی،
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات ژئوشیمی و پترولوژی
چکیده انگلیسی
We discuss the process of vulcanian eruptions on the basis of temporal variation of the texture of andesitic volcanic ash ejected from the Sakurajima volcano, Japan. Falling ash samples were collected every 2-50 min for petrological analysis. These ash samples contained juvenile particles, altered rock fragments, and fragments of crystals; here, we subdivide the juvenile particles into blocky, vesicular, and fluidal particles. Because the crystallinities of the vesicular and fluidal particles are lower than those of the blocky particles, we refer to the vesicular and fluidal particles as low-crystallinity particles (LCPs) and the blocky particles as high-crystallinity particles (HCPs). The temporal variation observed in ash texture reveals that the ratio of LCPs to HCPs (LCP/HCP) was small at the initiation of the eruption and increased as the eruption progressed. The higher microlite crystallinity in the HCPs indicates crystallization under lower pressures for longer durations relative to the LCP magma. The increase of the LCP/HCP ratio during a single vulcanian eruption suggests that the emission of less viscous gas-rich magma under a cap rock increases as the eruption progresses. Such temporal variation in ash texture reflects the transition from a sudden explosion to continuous ash emission during a vulcanian eruption.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Volcanology and Geothermal Research - Volume 260, 15 June 2013, Pages 80-89
نویسندگان
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